您可以导入CSV，在foreach中循环它，并使用$_（this）操作符，然后将IST导出为CSV
Somesthing like：

# import CSV
$list = import-csv P:\ath\to\file.csv -Delimiter ";" -Encoding Standard
# % means foreach
$list | % {
  # The grades is the key for each line
  # the first line of your csv represent the keys you can use
  # e.g. first colum: Name | Grade | Class
  # $_.Name | $_.Grade | $_.Class are your keys for every entry (2nd line and above)

  # here you can work with your grades an do what you want
  if($_.Grade -eq 11){
     # set a new value to the grade in the actual line
     $_.Grade = 2016
  }  
}

# now export the new list into csv
$list | export-csv P:\ath\to\new.csv -Delimiter ";" -NoTypeInformation

这应该是一个基本的工作。
Greetz Eldo.O

埃尔多，你的代码工作得很好。我不得不改变最后一行：

export-csv P:\ath\to\new.csv -Delimiter ";" -NoTypeInformation

到

$list | Export-Csv P:\ath\to\new.csv -Delimiter "," -NoTypeInformation

我还能够添加更多的if语句来完成我所需要的。